n‐GaAs substrates of varying doping levels were implanted with presumably electrically inactive ions like H, B, and As, and then annealed at high temperatures. Several experimental techniques were employed to detect and estimate the compensation in the implanted layers. We found the compensation in the proton‐implanted layers is alone dependent on the initial doping level of the substrate, while it is related to the ion introduced in the boron‐ and arsenic‐implanted layers. Along with these results, we present and discuss the preliminary results of the photoluminescence measurements performed to investigate the nature of the defects responsible for compensation.